Deep underwater, not too far from Guam, lies a crescent-shaped canyon called the Mariana Trench. It is home to the deepest known spot in the ocean: The Challenger Deep.

That’s what I found out from my friend Ray Lee. He teaches biology at Washington State University and studies animals that live in the deep sea.

A few explorers have made the nearly seven-mile journey to the Challenger Deep. Even though us cats aren’t big fans of water, I can imagine what it would be like to go there. We would have to go in a specially designed underwater vehicle, and we’d go through several different ocean zones along the way.

First, we’d pass through the Sunlight Zone. These are the brightest waters and we might see some fish, turtles, jellyfish, or stingrays swimming along.

We’d then pass through a part of the ocean called the Twilight Zone. Everything around us would start to get darker and darker. We might even see some critters making their own light, or bioluminescence, in the dark.

Next we’d pass through a part of the ocean called the Abyssal Zone. No sunlight would be able to reach us here. There would be no plants. The living conditions would be extreme, too. We might see extremely hot water from deep in the Earth erupting from chimney-like vents.

Lee is really curious about these vents and the creatures that are able to live in such extreme conditions. One of his favorite parts of his job is building instruments and devices that help us investigate these kinds of deep-sea environments.

The ocean can be a tricky place to study. It’s not only really dark, but the deeper you go, the greater the pressure of water pushing down on you. But Lee likes the challenge of exploring the mysterious deep.

“We are always interested in the unknown,” Lee said. “And the ocean has perhaps more things that are unknown than any other environment.”

Even deeper than the Abyssal zone is the Hadal Zone. This is where we find deep ocean trenches—and the Challenger Deep. I found out it wasn’t until pretty recently that scientists were able to go explore it.

James Cameron, an explorer and filmmaker known for “Titanic” and “Avatar,” piloted a one-man trip down to the Challenger Deep a few years ago. Before that, oceanographers Jaques Piccard and Don Walsh went to investigate.

They had to use special vehicles and equipment to reach these deep waters. Scientists have even set up underwater cameras that help us look at what life is like there. In the Hadal Zone, there are big mountains rising from the floor and possibly more sea vents. Scientists are learning about some of the creatures like sea cucumbers and really small crustaceans that call this part of our world home.

There is so much more to explore, Lawrence. Maybe one day, you’ll help us discover even more about our deep, vast oceans.